1. Field of the Invention
The present invention relates to a fruit-specific expression promoter from Solanum lycopersicum histidine decarboxylase gene and uses thereof. More specifically, the present invention relates to a fruit-specific expression promoter and 5′-untranslated region (herein below, abbreviated as “5′-UTR”) from Solanum lycopersicum histidine decarboxylase gene, a plant fruit-specific expression vector comprising the same, a plant transformed with the expression vector, a process for fruit-specific expression of a foreign gene by using the expression vector, and a transformed plant which expresses a foreign gene in a fruit-specific manner according to the process and seeds of the transformed plant.
2. Background Art
According to recent research trends, it is found that more studies are made on expression of a substance in plant as an eukaryotic organism compared to expression in bacteria as a prokaryotic organism. Such change is based on the fact that the substance obtained from a plant as an eukaryotic organism can be extracted more stably and occurrence of a possible change in the substance during a process like glycosylation is lower compared to bacteria (Albert et al., J Exp Bot. 59(10): 2673-2686. Published online 2008 May 31).
Previously developed 35S promoter is a very useful promoter having high efficiency for expression in every part of a dicot plant tissue, and thus it can be used most effectively for gene expression in plant. However, from the viewpoint of achieving expression of a specific substance in a desired tissue by transformation, a load to the plant is quite heavy as it involves with unnecessary expression. As such, a study to reduce unnecessary expression in stalk or leaf of a plant from which only a fruit is taken, for example a tomato, and to achieve specific expression in the fruit only is required. Tomato is one of the best candidates to study plants and, as the entire fruit flesh is eaten, its importance as a source for obtaining a certain substance by over-expression and intaking it as a raw or cooked material, or as a vaccine is being realized. From this point of view, it was confirmed recently that the tomato fruit is a good material for development of an oral vaccine (Giovanni Levia. EMBO Rep. 2000 Nov. 15; 1(5): 378-380). According to various recent studies related to vaccine, development of a vaccine using a crop like potato or sweet potato is widely carried out and a commercially available vaccine product has been already developed (Mason et al., Proc Natl Acad Sci USA. 1996 May 28; 93(11): 5335-5340). In this connection, it is aimed in this study to achieve fruit-specific expression of a substance based on development of a promoter which is overexpressed in a fruit-specific manner.
Since a fruit like a tomato can be eaten only after it is fully matured, if expression of a substance starts from a fruit at early-maturing period and is maintained until the late-maturing period, a great amount of the substance will accumulate in the fruit. To obtain such effect, a gene showing a certain level of expression or increasing expression during maturing period needs to be selected.
The inventors of the present invention selected, based on a microarray method, a gene which shows increasing or constant expression from the mature green stage to the red stage of a tomato fruit. Among the genes selected, the Solanum lycopersicum histidine decarboxylase gene was chosen as it showed the most favorable expression efficiency. Since expression of this gene is accumulated during a maturing process of a tomato fruit, i.e., its accumulation starts from the start of braking and is involved with ripening of a tomato fruit, it was believed that the gene may be also appropriate as a sought-after promoter having good expression efficiency.
Meanwhile, in Korean Patent Reg. No. 0784165, a promoter which regulates UDP-glucosyltransferase originated from a pepper, that is related to resistance of pepper plant against pathogenic infection and maturing process of a pepper fruit, is disclosed, and in Korean Patent Reg. No. 0574563, a highly efficient expression promoter from Arabidopsis thaliana and an expression vector comprising the promoter for highly efficient expression in plant are disclosed. However, these promoters are different from the promoter of the present invention.